1. Field of Invention
The present invention relates to a lighting device, and more particularly to a Light Emitting Diode (LED) illuminating module which is capable of generating a line of light source from a plurality of discrete points of light sources.
2. Description of Related Arts
Fluorescent lamps have long been utilized for a wide variety of lighting purposes, notably for advertisements and domestic use. People prefer fluorescent lamps to traditional light bulbs because they are generally more long-lasting and brighter when compared with traditional light bulbs. Moreover, each of such fluorescent lamps is capable of producing a line light source which is more preferable for practical use. For example, when a particular trademark has to be lightened, fluorescent lamps are suitable for generating consistent line of light of different shapes.
Yet in order to further enhance the lighting performance of the conventional fluorescent lamps, there exist some kinds of neon lights which are capable of producing high intensity of light from a line source. Such kinds of neon lights have successfully accomplished the task of producing high quality of light from consistent line sources. For example, a prominent US city where a substantial amount of neon lights have been utilized for advertisements is Las Vegas in the state of Nevada.
Despite the advantages and popularity of the conventional fluorescent lamps and neon lights, they definitely have discrepancies. First of all, a practical disadvantage of them is that they are generally fragile. As a matter of fact, almost all of the fluorescent lamps have an outer light tube which is generally made of transparent materials, such as glass. As a result, although the outer light tube is good for light transmission, it is fragile and vulnerable to external forces.
Second, conventional neon lights and fluorescent lamps will generate a substantial amount of heat when operating and therefore inevitably produce a substantial amount of energy waste. Although one might argue that the fluorescent lamps, when compared with conventional light bulbs, have already saved a lot of energy and produced a reduced amount of heat when operating. Nonetheless, the fact that the fluorescent lamps produce less amount of heat as compared with conventional light bulbs does not mean that the relevant problem is effectively remedied.
In addition, conventional fluorescent lamps will develop a substantial potential difference between their respective terminals so as to create a great risk to their user. When electricity leak occurred, the consequence would be catastrophic.
Moreover, the substantial potential difference, from engineering point of view, is created by electrons movement between the two terminals. As a result, when the fluorescent lamps are operating, they tend to be unstable in that a light pattern generated by the fluorescent lamp may follow the path of the electrons movement, thus creating a changing light pattern. This is especially true when the fluorescent lamp is nearly put of its product life-time.
Due to the above discrepancies, there exists another type of illuminating device which is generally called the Light Emitting Diode (LED). Conventionally, each LED is capable of generating light in a very efficient manner. It consumes less energy than conventional neon lights and fluorescent lamps, usually non-fragile, and generates only very little amount of heat when operating. One reason for this is that for LED, most energy inputted will be converted into light (i.e. electromagnetic wave with visual wavelength). Thus, as most energy inputted is converted into light, less heat is generated. Thus, LED seems to be a perfect substitute for the conventional neon lights and fluorescent lamps.
Nothing is perfect, however. A fatal disadvantage of LED is a by-product of the above-mentioned advantages. If one is trying to ask why LED consumes less energy, a probable answer might be that because LED produces lower light intensity. As a result, it is a usual practice that a plurality of LEDs is chained together to form a rope light or some other forms of illuminating devices for producing a desirable light effect. However, since each LED can only produce light from essentially a point source, when a plurality of LEDs is chained together, illumination of unsatisfactory pattern may be produced. Generally speaking, light of irregular pattern, meaning that it is not the kind of light coming from a point source nor a line source, ultimately results.
Technically, a point source of light would produce light which is radially extended therefrom to form a spherical pattern. On the other hand, a line source of light would produce light which is extended to form a cylindrical pattern. Thus, where a plurality of LEDs is chained together, the resulting light produced is not wholly spherical nor cylindrical. This produces unsatisfactory illumination effect for such conventional illuminating devices as rope light or light strip.